Working fluid composition for refrigerator and refrigeration oil
Disclosed is a working fluid composition for a refrigerating machine, comprising a refrigerating machine oil comprising an ester of a polyhydric alcohol and a fatty acid, a carbodiimide compound, and a phosphorous compound, and at least one refrigerant selected from 1, 1, 1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene, the fatty acid comprises at least one selected from fatty acids having 4 to 9 carbon atoms, and the carbodiimide compound and the phosphorus compound satisfy the conditions represented by the formula (1): 0.11 ≦ ( N C M C · W C ) ( N P M P · W P ) ≦ 4.70 ( 1 ) wherein, N c represents the number of carbodiimide groups per molecule of the carbodiimide compound, M c represents the molecular weight of the carbodiimide compound, W c represents the content of the carbodiimide compound, N p represents the number of phosphorus atoms per molecule of the phosphorus compound, M p represents the molecular weight of the phosphorus compound, and W p represents the content of the phosphorus compound.
1. A working fluid composition for a refrigerating machine, comprising:
a refrigerating machine oil comprising an ester of a polyhydric alcohol and a fatty acid, a carbodiimide compound, and a phosphorus compound; and
at least one refrigerant selected from 1, 1, 1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene;
wherein the polyhydric alcohol constituting the ester comprises pentaerythritol and dipentaerythritol,
the fatty acid constituting the ester comprises at least one selected from fatty acids having 4 to 9 carbon atoms, and the carbodiimide compound and the phosphorus compound satisfy conditions represented by the following formula (1):
0.11
≦
(
N
C
M
C
·
W
C
)
(
N
P
M
P
·
W
P
)
≦
4.70
(
1
)
wherein, N c represents a number of carbodiimide groups per molecule of the carbodiimide compound, M c represents a molecular weight of the carbodiimide compound, W c represents a content of the carbodiimide compound based on a total amount of the refrigerating machine oil, N p represents a number of phosphorus atoms per molecule of the phosphorus compound, M p represents a molecular weight of the phosphorus compound, and W p represents a content of the phosphorus compound based on a total amount of the refrigerating machine oil.
2. The working fluid composition for a refrigerating machine according to claim 1 , wherein the ester comprises a mixture of a first ester that is an ester of pentaerythritol and at least one fatty acid selected from fatty acids having 4 to 9 carbon atoms and a second ester that is an ester of dipentaerythritol and at least one fatty acid selected from fatty acids having 4 to 9 carbon atoms.
3. The working fluid composition for a refrigerating machine according to claim 2 , wherein a content of the second ester is 10% by mass or more and 40% by mass or less based on a total content of the first ester and the second ester.
4. The working fluid composition for a refrigerating machine according to claim 1 , wherein the refrigerating machine oil further comprises 0.1% by mass or more and 0.5% by mass or less of 2,6-di-tert-butyl-p-cresol based on the total amount of the refrigerating machine oil.
5. A refrigerating machine oil comprising:
an ester of a polyhydric alcohol and a fatty acid;
a carbodiimide compound; and
a phosphorus compound;
wherein the polyhydric alcohol constituting the ester comprises pentaerythritol and dipentaerythritol,
the fatty acid constituting the ester comprises at least one selected from fatty acids having 4 to 9 carbon atoms,
the carbodiimide compound and the phosphorus compound satisfy conditions represented by the following formula (1):
0.11
≦
(
N
C
M
C
·
W
C
)
(
N
P
M
P
·
W
P
)
≦
4.70
(
1
)
wherein, N c represents a number of carbodiimide groups per molecule of the carbodiimide compound, M c represents a molecular weight of the carbodiimide compound, W c represents a content of the carbodiimide compound based on a total amount of the refrigerating machine oil, N p represents a number of phosphorus atoms per molecule of the phosphorus compound, M p represents a molecular weight of the phosphorus compound, and W p represents a content of the phosphorus compound based on a total amount of the refrigerating machine oil, and
the refrigerating machine oil is used together with at least one refrigerant selected from 1,1,1,2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene.